TAILORx Results: Can a Gene-Expression Test Help Determine if Some Women with Breast Cancer Can Safely Avoid Chemotherapy?

BACKGROUND AND PURPOSE:

• There is a gene-expression assay that includes 21 genes with a score system (from 1-100) that predicts chemotherapy benefit
  • High: ≥31 (or some studies ≥26) is associated with a high risk of recurrence
  • Low: 0-10 predicts only 2% recurrence at 10 years, regardless of chemotherapy
  • Mid-range: 11-25, with limited data
• Sparano et al. (NEJM, 2018) examined the benefits of chemotherapy when the recurrence score falls in the mid-range

METHODS:

• Prospective randomized controlled trial (RCT)
  • Trial Assigning Individualized Options for Treatment (TAILORx) study
• Participants
  • Hormone-receptor-positive
  • Human epidermal growth factor receptor 2 (HER2)–negative
  • Axillary node–negative breast cancer
• Women assigned to
  • Recurrence score of ≤10: Endocrine therapy only
  • Score of ≥26: Chemotherapy plus endocrine (chemoendocrine) therapy
  • Score of 11-25 were randomized to the following arms
    • Endocrine therapy alone
    • Chemoendocrine therapy
  • Primary outcomes
    • Freedom from invasive disease recurrence
    • Second primary cancer
    • Death
  • Secondary outcomes
    • Freedom from recurrence of breast cancer at a distant site
    • Freedom from recurrence of breast cancer at a distant or local–regional site
    • Overall survival

RESULTS:

• 6,711 women had a midrange recurrence score (16-25)
• Primary outcomes: Endocrine therapy was noninferior to chemoendocrine therapy
  • Hazard Ratio (HR) 1.08; 95% CI, 0.94 to 1.24; P=0.26
• 9 years of follow up, groups had similar rates for the following
  • Invasive disease free survival
  • Freedom from disease recurrence at a distant site
  • Distant or local-regional site
  • Overall survival
• There was some benefit of chemotherapy found in women ≤50 years of age with a recurrence score of 16 to 25

CONCLUSION:

• Chemoendocrine therapy and endocrine therapy alone had similar effects for in women hormone-receptor-positive, HER2-negative, axillary node-negative breast cancer and a midrange 21-gene recurrence score
• Age did play a factor in benefits of chemotherapy, with younger women demonstrating some benefit

Learn More – Primary Sources:

Adjuvant Chemotherapy Guided by a 21-Gene Expression Assay in Breast Cancer